The United States emerged as the world’s sole superpower from the embers of the Cold War’s end, without, however, a wholesale reformulation of the principles and tools used to execute US grand strategy. This was particularly true in Europe, where the United States remained engaged politically, economically, and military; retained significant numbers of forward-deployed forces; and orchestrated the continuation and eventual expansion of NATO. For the United States, and for many Europeans, continued American dominance after 1991 of the continent’s security through NATO was a logical outgrowth of what Washington had provided in the West after 1945. Even within the context of America’s leadership of NATO, alternative strategies to the ultimate path of NATO’s post-1999 enlargement were possible. These included the Partnership for Peace, initially seen as an alternative to NATO enlargement formulated by the Pentagon; some enlargement of NATO to the east, but not as much as occurred; and a concrete path for Russia to join the alliance. This chapter considers the pros and cons of each of these alternatives to the NATO enlargement policy chosen by the United States and its partners in order to provide a more detailed assessment of the policy than has existed previously.

Immediately after the collapse of communism in Europe, many students of international relations predicted a return to balance-of-power politics among the great European powers. Others foresaw new balancing between the United States and Europe as the international system moved from a bipolar order to a multipolar world. A decade later, the distinguished observer Joseph Joffe argued that Western Europe and Russia might join together to offset American power: “Ten years after victory in the cold war, the United States is still No. 1 by any conceivable measure. But the lesser actors – Russia, Europe, China – are beginning to make true what history and political theory have predicted all along: Great powers will generate ‘ganging up.’ Nos. 2, 3, and 4 will seek to balance against Mr. Big.” And a recent book by a leading Europe scholar, Charles Kupchan, predicts that a united Europe will emerge as America's main long-term strategic challenger.

Joffe, Kupchan, and other realists like John Mearsheimer and Kenneth Waltz eventually may be right. Perhaps the German, French, and Russian coalition during the 2003 Iraq war is just the beginning. In the future, realpolitik and balance of power may return as the organizing principles of international politics on the European continent. Someday, the “lesser” powers may seek to balance against the United States. To date, however, what is more striking is how wrong these realist predictions since 1989 have proven to be.